HARRISBURG, Pa. -- Former U.S. Sen. Arlen Specter of Pennsylvania, the Republican-turned-Democrat who played a key role in many Supreme Court nominations, has died. He was 82.

His son Shanin Specter says his father died Sunday morning at his home in Philadelphia, from complications of non-Hodgkins lymphoma. He had battled cancer and other health problems.

Specter served 30 years in the Senate, a Pennsylvania record.

In April 2009, he startled fellow senators when he announced he was switching to the Democratic side because he did not think he could win the nomination for a sixth term in the increasingly conservative GOP. He wound up losing the 2010 Democratic primary to then-Rep. Joe Sestak, who narrowly lost Specter's seat to conservative Pat Toomey.

Specter was the chairman of the Senate Judiciary Committee before the Democrats regained power in 2007.